Propylene-based elastomeric composition

Abstract

The present invention includes a polyolefin elastomeric composition comprising a propylene-based elastomer having at least seventy five weight percent units derived from propylene, the propylene-based elastomer exhibiting a heat of fusion of from 1 to 35 Joules/gram, a weight average molecular weight of from 5400 to 875000 g/mol, and a permanent set of less than 40%; and a homogeneous ethylene-alpha olefin interpolymer having a molecular weight distribution of less than 3.5, a density from 0.885 to 0.915 g/ml, and a heat of fusion of from 65 to 125 Joules/gram, wherein the ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 97:3 to 80:20, and wherein the composition exhibits a heat of fusion from 2 to 55 Joules/gram, and a 2% secant flexural modulus of less than 69 MPa.

1. A polyolefin elastomeric composition, the composition consisting essentially of:
 (a) a propylene-based elastomer having at least seventy five weight percent (75 wt %) units derived from propylene and from ten to twenty five weight percent (10-25 wt %) units derived from a C2, or a C4-C10 alpha olefin, the propylene-based elastomer exhibiting:
 (1) a heat of fusion by DSC analysis of from 1 Joules/gram to 35 Joules/gram; 
 (2) a weight average molecular (Mw) of from 54000 to 875000 g/mol; and 
 (3) a permanent set of less than 40%; and 
 
 (b) a homogeneous ethylene-alpha olefin interpolymer selected from a substantially linear polyethylene and a homogeneously branched linear polyethylene having a molecular weight distribution (Mw/Mn) of less than 3.5, a density from 0.885 to 0.915 g/ml, and a heat of fusion of from 65 to 125 Joules/gram, wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 97:3 to 80:20, and wherein the composition exhibits a heat of fusion from 2 to 55 Joules/gram, and a 2% secant flexural modulus of less than 69 MPa. 
 
     
     
       2. The polyolefin elastomeric composition of  claim 1 , wherein the propylene-based elastomer has a molecular weight distribution (Mw/Mn) of less than 3.5. 
     
     
       3. The polyolefin elastomeric composition of  claim 1 , wherein the homogeneous alpha olefin interpolymer has a refractive index from 1.496 to 1.516. 
     
     
       4. The polyolefin elastomeric composition of  claim 1 , wherein the homogeneous alpha olefin interpolymer has a refractive index from 1.503-1.509. 
     
     
       5. The polyolefin elastomeric composition of  claim 1 , wherein the homogeneous alpha olefin interpolymer has a refractive index of from 1.505 to 1.507. 
     
     
       6. The polyolefin elastomeric composition of  claim 1 , wherein the homogeneous ethylene-alpha olefin interpolymer comprises a C4 to C1O alpha olefin. 
     
     
       7. The polyolefin elastomeric composition of  claim 1 , wherein the homogeneous ethylene-alpha olefin interpolymer comprises a C4, C6, or C8 alpha olefin and the interpolymer exhibits a 2% secant flexural modulus of from 27 to 131 MPa. 
     
     
       8. The polyolefin elastomeric composition of  claim 1 , wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 95:5 to 85:15. 
     
     
       9. The polyolefin elastomeric composition of  claim 1 , wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 90:10 to 85:15. 
     
     
       10. The polyolefin elastomeric composition of  claim 1 , wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 97:3 to 90:10. 
     
     
       11. The polyolefin elastomeric composition of  claim 1 , wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 96:4 to 92:8. 
     
     
       12. The polyolefin elastomeric composition of  claim 5 , wherein the homogeneous ethylene-alpha olefin interpolymer comprises an ethylene 1-octene copolymer and wherein the ethylene 1-octene copolymer has a density of from 0.890 to 0.910 g/mL. 
     
     
       13. The polyolefin elastomeric composition of  claim 1 , wherein the peak crystallization temperature is at least 20° C. and at least 20° C. higher than the peak crystallization temperature of the propylene-based elastomer. 
     
     
       14. The polyolefin elastomeric composition of  claim 1 , wherein the propylene-based elastomer has from 11 to 19 weight percent units derived from ethylene. 
     
     
       15. The polyolefin elastomeric composition of  claim 1 , wherein the propylene-based elastomer exhibits a heat of fusion of from 2 to 25 Joules/gram. 
     
     
       16. A polyolefin elastomeric composition, the composition consisting essentially of:
 (a) a propylene-based elastomer having at least seventy five weight percent (75 wt %) units derived from propylene and from eleven to seventeen weight percent (11-17 wt %) units derived from ethylene, the propylene-based elastomer exhibiting:
 (1) a heat of fusion by DSC analysis of from 2 Joules/gram to 15 Joules/gram; 
 (2) a molecular weight distribution (Mw/Mn) of less than 3.5; 
 (3) a melt flow rate of from 2 to 30 g/10 minutes; and 
 (4) substantially isotactic propylene sequences; and 
 
 (b) a homogeneous ethylene-alpha olefin interpolymer selected from a substantially linear polyethylene and a homogeneously branched linear polyethylene comprising from 91 to 97 mole percent units derived from ethylene and 3 to 9 mole percent units derived from an alpha olefin having from 4 to 12 carbon atoms and having a density of from 0.890 to 0.910 g/ml, a molecular weight distribution (Mw/Mn) of less than 3.5, an index of refraction from 1.503 to 1.509, and a heat of fusion of from 75 to 115 Joules/gram, wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 97:3 to 80:20, and wherein the composition has a molecular weight distribution (Mw/Mn) of between 1.7 and 10 and exhibits a heat of fusion from 2 to 55 Joules/gram, a peak crystallization temperature of at least 20° C., and a 2% secant flexural modulus of less than 67 MPa. 
 
     
     
       17. A polyolefin elastomeric composition, the composition consisting essentially of:
 (a) a propylene-based elastomer having at least seventy five weight percent (75 wt %) units derived from propylene and from twelve to sixteen weight percent (12-16 wt %) units derived from ethylene, the propylene-based elastomer exhibiting:
 (1) a heat of fusion by DSC analysis of from 2 Joules/gram to 12 Joules/gram; 
 (2) a molecular weight distribution (Mw/Mn) of less than 3.5; 
 (3) a melt flow rate of from 2 to 30 g/10 minutes; and (3) substantially isotactic propylene sequences; and 
 
 (b) a homogeneous ethylene-alpha olefin interpolymer selected from a substantially linear polyethylene and a homogeneously branched linear polyethylene comprising from 91 to 97 mole percent units derived from ethylene and 3 to 9 mole percent units derived from an alpha olefin having from 4 to 8 carbon atoms and having a density of from 0.895 to 0.905 g/ml, a molecular weight distribution (Mw/Mn) of less than 3.0, an index of refraction from 1.505 to 1.507, and a heat of fusion of from 89 to 101 Joules/gram, wherein the weight ratio of the propylene-based elastomer to the homogeneous ethylene-alpha olefin interpolymer is from 90:10 to 84:16, and wherein the composition has a molecular weight distribution (Mw/Mn) of between 2.0 and 5.0, exhibits a heat of fusion from 2 to 50 Joules/gram, a peak crystallization temperature of at least 40° C., and a 2% secant flexural modulus of less than 30 MPa.